1. Field of the Invention
The present invention is an improved construction of plastic parts used in manually propelled lawnmowers.
2. Description of the Related Art
As disclosed in the aforementioned co-pending applications, every effort is made to protect the operator of a manual pushed walk around grass cutter by constantly scrutinizing the device for opportunities to improve on the safety factor.
Those applications focused on an area in need of improvement involving grass cutters that can be used with or without grass bag attachments. Those grass cutters usually have a spring-loaded door permanently attached as part of the cutter body itself. When the cutter is used without a grass bag attached, the door is spring loaded closed, however, when a grass bag is used, its installation process requires that the spring-loaded door be hand held open. The entire bag and assembly is attached to the mower and the spring-loaded door is released. The door then rests on the surface of the plastic trim that surrounds the entire opening of the grass bag itself. The problem is that air escaping between the plastic trim on the bag, and the door surface (referred as blow back) is sufficient enough to cause concern for the operator's safety.
The solutions disclosed in the my aforementioned co-pending applications involve the use of certain materials and making certain structural changes in profile so as to reconfigure the plastic trim that contacts the door surface, including the introduction of a small hollow ball as part of the plastic profile or use of a flap to seal the door. The plastic material used in the co-pending applications solved the problems caused by the pressure from the spring-loaded door compressing part of the ball or the flap as the case may be producing a good intimate contact between the spring-loaded door and the material of choice. As is known in the art, after hours of use, as the grass cutter tends to heat up, the hollow ball on the one hand or the flap on the other hand assumes a permanent set, so that when the grass bag is removed, the ball or the flap becomes permanently distorted from the pressure from the spring loaded door and the elevated temperature.
The second plastic material for the hollow ball or the flap has many obstacles to overcome:                1. The adhesion between the two materials has to be intense enough to prevent separation between the two materials.        2. The hollow ball or the flap should be flexible enough to compress on contact with the door.        
The plastic material manufactured by Advanced Elastomer Systems, Akron, Ohio solved all of the above named problems. These products are commonly referred to as TPE (Thermoplastic Elastomer) one of which is sold under the trademark SANTOPRENE.